socket_write

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

socket_write — Write to a socket

Description

socket_write(Socket $socket, string $data, ?int $length = null): int|false

The function socket_write() writes to the socket from the given data.

Parameters

socket
data: The buffer to be written.
length: The optional parameter length can specify an alternate length of bytes written to the socket. If this length is greater than the buffer length, it is silently truncated to the length of the buffer.

Return Values

Returns the number of bytes successfully written to the socket or false on failure. The error code can be retrieved with socket_last_error(). This code may be passed to socket_strerror() to get a textual explanation of the error.

Note:
It is perfectly valid for socket_write() to return zero which means no bytes have been written. Be sure to use the === operator to check for false in case of an error.

Changelog

Version	Description
8.0.0	`socket` is a Socket instance now; previously, it was a resource.
8.0.0	`length` is nullable now.

Notes

Note:
socket_write() does not necessarily write all bytes from the given buffer. It's valid that, depending on the network buffers etc., only a certain amount of data, even one byte, is written though your buffer is greater. You have to watch out so you don't unintentionally forget to transmit the rest of your data.

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User Contributed Notes 5 notes

down

revelable at hotmail dot com ¶

13 years ago

Here we have the same function to write a socket but with improved performance.

If the messager are not larger, they will be written entirely with a single socket_write() call. And is not needed to call the substr() function for the first bucle.

<?php
$st="Message to sent";
$length = strlen($st);
        
    while (true) {
        
        $sent = socket_write($socket, $st, $length);
            
        if ($sent === false) {
        
            break;
        }
            
        // Check if the entire message has been sented
        if ($sent < $length) {
                
            // If not sent the entire message.
            // Get the part of the message that has not yet been sented as message
            $st = substr($st, $sent);
                
            // Get the length of the not sented part
            $length -= $sent;

        } else {
            
            break;
        }
            
    }
?>

down

anonymous ¶

3 years ago

sending a few mbs or more results in incomplete transfers, send data in a loop and chunks instead, socket_write reports complete write even though it is only a partial transfer, possibly because of buffer overrun somewhere.

$strlen=strlen($msg);
$totaltransferred=0;

$blocksize=10000;
for ($a=0;$a<$strlen;$a+=$blocksize){
    $part=substr($msg,$a,$blocksize);
    $transferred=socket_write($socket,$part,strlen($part));
    $totaltransferred+=$transferred;
}
    
if ($totaltransferred<$strlen){
    echo "incomplete transfer";
}

down

gtk at linux dot online dot no ¶

22 years ago

from http://www.manualy.sk/sock-faq/unix-socket-faq-2.html
read() is equivalent to recv() with a flags parameter of 0. Other values for the flags parameter change the behaviour of recv(). Similarly, write() is equivalent to send() with flags == 0.

down

php at deguest dot asia ¶

9 years ago

I often read in php docs users not checking for the php function returned value, and in the case of socket_write, I could not see here in the comment anyone botering to read on the socket the server reply.

Then one user thought it would be a good idea to use usleep after a socket_write on a smtp connection.

Actually, if you check the server reply, not only will it give time for the server to reply before you write again on the socket, but also this is a great opportunity to check what the server replied you.

For instance, for smtp connection :

In this example MAIL_SERVER, MAIL_PORT and DEBUG are constants I defined.

<?php

function sendmail( $param )

{

    $from    = &$param[ 'from' ];

    $to      = &$param[ 'to' ];

    $message = &$param[ 'data' ];

    

    $isError = function( $string )

    {

        if( preg_match( '/^((\d)(\d{2}))/', $string, $matches ) )

        {

            if( $matches[ 2 ] == 4 || $matches[ 2 ] == 5 ) return( $matches[ 1 ] );

        }

        else

        {

            return( false );

        }

    };

    

    try

    {

        $socket = null;

        if( ( $socket = socket_create( AF_INET, SOCK_STREAM, SOL_TCP ) ) == false )

        {

            throw new Exception( sprintf( "Unable to create a socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        if( !socket_connect( $socket, MAIL_SERVER, MAIL_PORT ) ) 

        {

            throw new Exception( sprintf( "Unable to connect to server %s: %s", MAIL_SERVER, socket_strerror( socket_last_error() ) ) );

        }

        $read = socket_read( $socket, 1024 );

        if( $read == false )

        {

            throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        

        if( socket_write( $socket, sprintf( "HELO %s\r\n", gethostname() ) ) === false )

        {

            throw new Exception( sprintf( "Unable to write to socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        $read = socket_read( $socket, 1024 );

        if( $read == false )

        {

            throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        else

        {

            if( ( $errCode = $isError( $read ) ) ) throw new Exception( "Server responded with an error code $errCode" );

        }

        

        if( socket_write( $socket, sprintf( "MAIL FROM: %s\r\n", $from ) ) === false )

        {

            throw new Exception( sprintf( "Unable to write to socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        $read = socket_read( $socket, 1024 );

        if( $read == false )

        {

            throw new Exception( sprintf( "Unable to read from socket: %s", socket_strerror( socket_last_error() ) ) );

        }

        else

        {

            if( ( $errCode = $isError( $read ) ) ) throw new Exception( "Server responded with an error code $errCode" );

        }

        /* And some more code, but not enough place in comment */

        return( $totalWriten );

    }

    catch( Exception $e )

    {

        $ERROR = sprintf( "Error sending mail message at line %d. ", $e->getLine() ) . $e->getMessage();

        return( false );

    }

}

down

-3

webmaster at you-are-infected dot com ¶

18 years ago

If you connect to a Server in a way like you do with telnet or some similar protokoll you may have problems with sending data to the server. I found out that at some servers there is a different between:

<?php
    
    socket_write ($my_socket, $line, strlen ($line));
    socket_write ($my_socket, "\r\n", strlen ("\r\n"));
    
?>
witch worked at least, and 
<?php
    socket_write ($my_socket, $line."\r\n", strlen ($line."\r\n"));
?>
wich made the server stop sending any data.

I hope this helps to save a lot of time. I needed about two days to find out, that this was the problem ;)

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socket_write

Description

Parameters

Return Values

Changelog

Notes

See Also

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User Contributed Notes 5 notes